About 40% of the daily calorie intake of the average American diet is provided by fats (e.g. triglycerides) which are hydrolyzed and which are subsequently absorbed during digestion. While fats are necessary for balanced nutrition, the average consumer consumes more than is needed for proper nutrition. Furthermore, the sharp increase in consumption of fast foods in the American diet is thought to be a major contributor to the increase in the amount of dietary fat because fast foods, which typically rely on frying, contain relatively large amounts of fats. The high level of fats in the diet is thought to contribute to serious health problems, such as heart disease, arteriosclerosis, and obesity. A reduction in the caloric intake can be significantly enhanced by a reduction in the intake of dietary fat, since fats have about twice the caloric density of proteins and carbohydrates. Consequently, there is a great commercial demand for low fat, low calorie food products, especially snack foods such as potato chips, but with the palate appeal of the original fat-containing product. Unfortunately, all too often, low fat and no-fat means an inferior tasting food product when compared to the original full fat product.
One approach to making low fat and no-fat food products, particular snack food products is to do so without frying. For example, U.S. Pat. No. 4,756,916 teaches a process for producing low-fat potato chips by first washing potato slices with an aqueous solution, then applying oil to the washed slices to coat the slices with oil. The oil coated slices are then blanched, essentially pre-frying the slices due to the oil coating, then baked at a temperature of at least about 390.degree. F. to partially dry the slices. The partially dried potato slices are then baked at a temperature of about 290.degree. F. (140.degree. C.) to 320.degree. F. (160.degree. C.) to finish drying the slices. Other non-frying techniques are taught U.S. Pat. Nos. 4,906,483; 4,873,093; 4,919,965; 5,298,707; and 5,370,898. All of the resulting products from these processes do not have the palate appeal of the equivalent fried version.
Another approach is taught in co-pending U.S. patent application Ser. No. 08/256,258, filed Dec. 31, 1992 wherein fat is removed from prepared foods by use of a normally gaseous solvent, preferably butane, propane, and mixtures thereof. Such a process is capable of producing fried snack foods, particularly potato chips, which are substantially fat free and which have the palate appeal of conventional snack foods fried in vegetable oil.
Other approaches to producing foods low in fats and calories is to use a fat substitute in place of at least a portion of conventional triglyceride fat. Much research and development is taking place to produce fat substitutes. For example, Protor and Gamble have a line of fat subsitutes referred to Olestra, which they are trying to get approved by the FDA. Nabisco is marketing a fat substitute call Salatrim, which is reported to have 5 calories per gram and consists of three fatty acids attached to a glycerol, but includes primarily long-chain stearic acid, which the body absorbs poorly, and either acetic, propionic, or butyric short-chain acids, which have fewer calories than other fatty acids. Pfizer is developing a fat subsitute they refer to as Veri-Lo which is a fat extender based on oil-in-water and fat-in-water emulsions of common substances such as soybean oil and milk fat. Pfizer is also working on a product called Litesse, which is an improved version of the polydextrose which Pfizer has been selling for some time. Nutrasweet is marketing a product called Simplesse which has only 1 to 2 calories per gram; National Starch has N-Lites, which is manufactured from starch; and A.E. Staley Manufacturing Co. has Stellar which is an acid hydrolyzed starch.
One major strategy for developing low calorie replacement fats has been to structurally re-engineer natural triglycerides in such a way as to retain their conventional functional properties in foods, while removing their susceptibility toward hydrolysis and subsequent absorption into the body during digestion. To this end, the fatty acids attached to glycerol have been replaced with alternative acids (U.S. Pat. No. 3,579,548); groups have been inserted between the fatty acids and the glycerol backbone ("propoxylated glycerols", European Patent No. 254,547); the ester linkages have been replaced by ether linkages (U.S. Pat. No. 3,818,089); the ester linkages have been reversed (U.S. Pat. No. 4,508,746); and the glycerol moiety has been replaced with an alternate alcohol (e.g., ethylene glycol in U.S. Pat. Nos. 2,924,528 and 2,993,063).
A second major strategy for the development of a low calorie fat substitutes has been to synthesize non-absorbable polymeric materials which are structurally unlike triglycerides, but which have physical properties, such as mouthfeel, similar to edible fats. Mineral oil was disclosed as a fat substitute as early as 1894 (U.S. Pat. No. 519,980), and more recently, polydextrose (U.S. Pat. No. 4,631,196), polyglucose and polymaltose (U.S. Pat. No. 3,876,794), polysiloxane (European Patent No. 205,273), jojoba wax (W. German Patent No. 3,529,564), and polyethylene polymers (E. German Patent No. 207,070) have also been suggested.
A third major strategy combines the first two. Rather than restructure triglyceride molecules or find a substitute which is structurally very dissimilar to triglyceride molecules, this third approach involves the use of various polyolester compounds, as non-absorbable fat substitutes, which have numbers of fatty acid groups in excess of the three found in conventional fat triglycerides. The polyester compositions are typically nondigestible mixtures of sucrose hexa-, hepta-, and octa- fatty acid esters. Also, fully esterified sugars were suggested as fat substitutes during World War I (notably mannitol, Lapworth, A., and Pearson, L. K., and Halliburton, W. D., et al., 13 J Biol. Chem. 296 and 301 (1919)), and the Southern and Western Regional Research Laboratories of the U.S.D.A. investigated the feasibility of using amylose esters as new-type fats during the 1960's (see Booth, A. N., and Gros, A. T., 40 J. Amer. Oil Chem. Soc. 551 (1963). More recently, sucrose polyesters have been suggested (U.S. Pat. No. 3,600,186). The caloric availability and digestibility of a series of dimeric and polymeric glycerides including diglyceride esters of succinic, fmaric, and adipic acids, and polymeric fats from stearic, oleic and short-chain dibasic acids were assessed by the U.S.D.A. group cited supra, and polyglycerol esters have since been suggested (U.S. Pat. No. 3,637,774).
While a multitude of fat substitutes has been proposed, there are serious questions as to health risks that may arise if significant amounts of such compositions find their way into the diet. For example, non-digestible fats, at moderate to high levels, have serious problems because they: (i) act as a laxative and are passed through the body causing anal leakage; (ii) absorb valuable minerals and vitamins from the body; and (iii) elicit foreign body reactions like those early documented for mineral oil. Therefore, there is a need to reduce the level of fat substitutes to safer levels in foods containing same.